Infrared detector cells, and corresponding arrays, are used to produce images in situations where optical imaging is not effective, such as in darkness, or where infrared signatures provide additional information about the target.
Continuing objectives in the design of infrared detectors are to increase detectivity performance (D*) and to increase the resistance of the diode detectors.
A prior heterojunction photovoltaic refractive resonant optical cavity infrared detector which has thermal detector regions, but is configured as a large area detector, is described in "The Resonant-Optical-Cavity HgCdTe Heterojunction Photodiode--A New Device for 10.6 .mu.m Heterodyne Detection at 2 GHz", by R. B. Broudy, D. R. Resler, P. W. Pastel, M. B. Reine and C. C. Wang in Proc. IRIS Detector, 1987, Vol. III, p. 189-200.